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The Beyond Einstein Program Assessment Committee (BEPAC) is currently reviewing EXIST and other Beyond Einstein mission concepts. Four public town meetings were held around the country Feb - Apr 4, 2007.
Jan 30, 2007
EXIST Presentation to BEPAC
» Download it now: PDF
Nov 7, 2006
EXIST Presentation to BEPAC
» Download it now: PowerPoint, PDF
Aug 2006
Progress on CZT Detectors
» ProtoEXIST CZT Detectors
» EXIST CZT Detectors
» Recent Papers
May 2006
Scanning Mode Tests
Tests of EXIST-style scanning mode with Swift (BAT slew survey) show excellent imaging performance.
Summary
The Energetic X-ray Imaging Survey Telescope (EXIST) is a proposed hard X-ray imaging all-sky deep survey mission and was recommended by the 2001 Report of the Decadal Survey. It is a strong candidate to be the Black Hole Finder Probe, one of the three "Einstein Probes" in the Beyond Einstein Program described in the current Roadmap for NASA Space Science missions. EXIST is based on proven technology and could be launched by ~2015.
EXIST would image and temporally resolve the entire sky each 95-minute orbit, detecting extremely faint high energy X-ray sources in an energy range (3-600 keV) that is poorly explored but particularly important for the discovery and study of black holes. With its unparalleled sensitivity at hard X-ray energies, EXIST will allow the study of black holes on all size scales, with masses ranging from a few to more than one billion times the mass of the Sun. EXIST science objectives and mission characteristics are summarized in a one-page overview.
Science
The primary EXIST Science Objectives are to observe:
- Obscured or dormant super-massive black holes to probe SMBH properties and evolution, the origin of the cosmic X-ray background (CXB), and the accretion luminosity of the universe
- The birth of stellar black holes (BHs) in cosmic gamma-ray bursts (GRBs) to probe GRB origins, derive photometric z's (redshift distances), and map cosmic structure and evolution out to z > 6-10.
- Non-thermal jets from black holes to constrain BH-jet physics, the cosmic infra-red (IR) background, and the nuclear luminosity of the universe
- Stellar and intermediate-mass black holes (IMBHs) in the Galaxy and Local Group to constrain BH numbers, properties, formation, and evolution.
Secondary science objectives include surveys for: 511-keV positron-electron annihilation lines in BHs, jets, and classical novae; soft gamma-ray repeater (SGR) superflares and magnetars out to 150 Mpc; 44Ti emission, to find obscured supernova remnants (SNRs) and determine the SN rate in the Galaxy.
Instruments
Because X-rays with energies above ~10 keV can only be focussed in very narrow fields of view unsuitable for wide-field surveys, EXIST uses coded mask apertures for imaging. There are two sets of coded mask telescope systems, plus a dual particle/photon detector:
- The High Energy Telescope (HET) is the primary instrument, consisting of 19 wide-field hard X-ray telescopes. It covers the 10-600 keV band with 6 arcminute resolution over a 154° x 65° field of view, using 6 square meters of CZT detectors.
- The Low Energy Telescope (LET) complements the HET with energy coverage from 3-30 keV and finer spatial resolution (1', with 10" position accuracy) using 1.3 square meter of silicon detectors. The LET covers 160° x 54° field of view with 32 sub-telescopes. The LET enables accurate registration of hard X-ray sources detected by HET with sources seen (or not seen) in other wavebands (optical, infrared, etc.)
- The HET Anti-COincidence System (HACOS) employing CsI scintillators rejects particle-background events (from cosmic rays) and also measures GRB spectra at energies from a few hundred keV to 20 MeV.